<html>
  <head>
    <script type="application/javascript">
      function draw() {
        var ctx = document.getElementById("canvas").getContext("2d");
        for (var i = 0; i < 6; i++) {
          for (var j = 0; j < 6; j++) {
            ctx.fillStyle =
              "rgb(" +
              Math.floor(255 - 42.5 * i) +
              "," +
              Math.floor(255 - 42.5 * j) +
              ",0)";
            ctx.fillRect(j * 25, i * 25, 25, 25);
          }
        }
      }
    </script>
  </head>
  <body onload="draw();">
    <canvas id="canvas" width="300" height="300"></canvas>
  </body>
</html>
